From the point of view of the prevention of global warming and energy saving, efficiency regulation (top runner regulation) of three-phase induction motors which account for 80% of the market of electric motors (capacity base, production statistics 2008 by Ministry of Economy, Trade and Industry) is carried out. The efficiency of the three-phase induction motors is provided in JIS C43034-30 (IEC60034-30) as IE1 (standard efficiency), IE2 (high efficiency), and IE3 (premium efficiency). In the present situation, most of shipments are graded IE1, and are regulated to switch to IE3.
Mounting dimensions (frame numbers) of the three-phase induction motors are provided in JIS C 4210, and users/manufacturers (e.g. equipment manufacturers) design equipment accordingly. Therefore, products compatible with the current products are required.
In pursuit of further energy saving, IE4 (super premium efficiency) is to be provided. IE4 is difficult for the three-phase induction motors to achieve, so that synchronous motors using permanent magnets (which may be hereinafter referred to as permanent magnet type rotary electric machines) are used to improve efficiency.